Commodore Amiga A2000 - Page 153

EXAMPLE
This example details the system audio DMA action in a step-by-step fashion.
Suppose you wanted to join together a sine and a triangle waveform, end-to-end, for a
special audio effect, alternating between them. The following sequence shows the action
of your program as well as its interaction with the audio DMA system. The example
assumes that the period, volume, and length of the data set remains the same for the
sine wave and the triangle wave.
INTERRUPT PROGRAM
If (wave = triangle)
write AUD0LCL with address of sine wave data.
Else if (wave = sine)
write AUD0LCL with address of triangle wave data.
MAIN PROGRAM
1. Set up volume, period, and length.
2. Write AUD0LCL with address of sine wave data.
3. Start DMA.
4. Continue with something else.
- 144 Audio Hardware -